Chosen Solution
What is the part to the right when looking at to forward facing camera? It’s rectangular with a ribbon.
Cellular antenna and cable assembly. Your iPad isn’t a wifi-only device. Well, at least, it wasn’t before you cut it.
That would be probably a cellular antenna, but if you didn’t see a Sim slot it is a Bluetooth antenna. If you think you damaged it, the I would suggest putting it together, and turning it on to see what it was. If it was something you used, then consider purchasing a replacement (if available).
